1. Field of the Invention
The invention relates to a method and apparatus for monitoring temperature during aerobic composting of organic waste matter.
2. Discussion of the Prior Art
It is known to compost organic waste material, such as sludge from a waste water treatment facility or garbage, utilizing mechanical composting bins or vessels and pressurized aeration channels. The goal is to produce a nonodorous organic material which can often be sold as a soil amendment and which at least is not costly and objectionable to dispose of. In the process, the amount of water in the composting material is reduced, thus resulting in drying of the organic matter to further alleviate the disposal problem.
The usual proposals for mechanical composting have involved upright, cylindrical devices in the nature of silos through which pressurized aeration air is circulated to aid in the decomposition process. As an alternative to vertical composting silos, it is known to provide a horizontal composting method and apparatus of a simple construction in which organic matter is moved horizontally along the length of the composting vessel in a stepwise fashion with the use of an actuated ram. Diffusers have been used along the length of the vessel to inject aeration air into the organic matter to aid in carrying out the composting process in a relatively short period of time by controlling the temperature.
This temperature control is a critical part of the composting process. If the temperature of the organic matter is too low, the process will take too long to complete. On the other hand, if the temperature is too high, the process breaks down. The key to economically operating whatever equipment is used in the composting process is to achieve an optimum temperature for a selected time period in order to quickly and completely process the organic matter. One example of such a temperature and time period is to achieve an optimum temperature of 55.degree. C. for three days. In order to achieve this, the temperature of the organic matter must be controlled, and in order to control the temperature, some means of temperature monitoring is required.
In order to control the temperature of the composting mass to the desired temperature in the horizontal composters using air to accelerate the process, a monitoring device is necessary to provide the temperature at a plurality of points throughout the mass.
Temperature monitoring devices located at the perimeter of the composting chamber cannot provide appropriate temperature readings. Thus, a temperature monitoring device or method which probes into the mass of the organic matter is desired.
A problem connected with monitoring temperature at the mid-point is related to the fact that the composting mass of organic matter moves through the composter and therefore any monitoring device used must accommodate such movement.